Patent GB-849261-A (GB)
Title: Improvements in or relating to clock controlled mechanism for use between a power sou
Inventor: FLUMM PAUL
IPC: G04C23/16
Filed: 1955-10-24
Abstract: 849,261. Time switches. SMITH & SONS (ENGLAND) Ltd., S. Oct. 24, 1956 [Oct. 24, 1955; Oct. 25, 1955], Nos. 30335/55 and 30530/55. Class 38 (5). A clock-controlled mechanism for use between a power source and a device to be energized thereby comprises means for actuating a cut-in device and means for actuating a cut-out device, a clockwork drive-shaft arranged to actuate said devices respectively through two transmissions embodying adjustable differential gear mechanisms, whereby the times at which the power supply may be cut in and cut out may be varied separately by a single adjusting- member. An embodiment for use with an electric cooker is described in which a synchronous electric motor (not shown) drives a gear-wheel 1 and the usual minute and hour hands 2 and 3 through conventional motion work (not shown, but indicated by the broken spindles). The gear-wheel I also drives a gear-wheel 4 carrying two planet-wheels 5 and 6 mounted on a short spindle 7 extending through it. The planetwheel 5 engages a sun-wheel 13 to which is secured a cam 14, while the planet-wheel 6 engages a sun-wheel 8 carried on the same shaft as a further wheel 9. The drive from the synchronous motor is also taken to a wheel 4<SP>1</SP> as indicated by the upper chain-dotted line. This wheel 41 carries planet-wheels 5<SP>1</SP> and 6<SP>1</SP> engaging sun-wheels 13<SP>1</SP> and 81 to move a second cam 17 and wheel 9<SP>1</SP>, respectively. If the wheels 9 and 9<SP>1</SP> are kept stationary the cams 14 and 17 revolve once in twelve hours and their positions relative to the time shown by hands 2 and 3 may be controlled by adjustment of the wheels 9 and 9<SP>1</SP>. The wheel 91 engages a wheel 21 pinned on a shaft 22 positioned by knob 23, and the wheel 9 engages a wheel 10 loosely mounted on shaft 22. The wheels 10 and 21 are normally held stationary by friction clutches 11. The wheel 9 also engages a wheel 12 connected to a pointer or disc 15 moving over the same scale as hands 2 and 3, and the gear ratio is such that if wheel 1 is kept stationary the wheel 12 rotates through the same angle as cam 14. The wheel 9<SP>1</SP> is similarly coupled, as indicated by the lower chain-dotted line, to a wheel 12<SP>1</SP> and pointer or disc 18 to show the relative setting of cam 17. A projection 20 on the wheel 21 is capable of engaging a corresponding projection 19 on wheel 10 such that the knob 23 may be used, by virtue of the lost-motion connection provided by projections 19 and 20, to position both the indicators 15 and 18 independently, and thus to set the cams 14 and 17 relative to the drive-wheel 1. The cams 14 and 17 may control a switch, as described in Specification 766,670. As shown in Fig. 3, a switch-actuating arm 44 is restrained by cam 14 against the action of a spring 46. Its cam surface 47 holds the two bridging members 50 away from contacts 51 by pressing on the lower end of a spring- loaded pivoted carrier-plate 48. When the cam 14 releases the arm 44 it swings over against cam 17 and releases its pressure on the plate 48 whereby the members 50 bridge the contacts 51. When the cam 17 releases the arm 44 further movement of its cam surface 47 again causes the members 50 to be withdrawn from contacts 51. A second embodiment (Fig. 2, not shown), has slight modifications of the layout of the various gear trains and the indicator 18 is replaced by a disc and the pointer 15 by an arm carrying an annulus which passes through a radial slot at the edge of the disc. The disc is preferably black and the annulus white or of a contrasting colour, the amount of annulus visible above the disc giving the required indication.